NR1H4 and animal viral hepatitis: Importantly, the final differentiated cells exhibited high expression levels of Na+ −taurocholate co-transporting polypeptide (NTCP) and farnesoid X receptor or bile acid receptor (FXR) (Fig. 6e), which are known essential mediators for hepatitis B virus entry of hepatocytes and hence, suggesting this hepatic differentiation system may be used for liver disease modeling of viral hepatitis.